Portable internal combustion engine



May 23, 1939. D. R. CLARKE PORTABLE INTERNAL COMBUSTION ENGINE FiledAug. 30. 1937 2 Sheets-Sheet l INV EN TOR lll Il I :sul 5 lun:

DOUGLAS R.CLR K E BY ATTORNEYS May 23, 1939. D. R. CLARKE PORTABLEINTERNAL COMBUSTION ENGINE Filed Aug. 50, 1937 2 Sheets-Sheet INVENTORDOUGLAS R.CLARK MMM Patented May 23, 1939 UNITED STATES PATENT OFFICEPORTABLE INTERNAL COMBUSTION ENGINE 8 Claims.

This invention relates generally to internal combustion engines of thetype employed for marine purposes and has particular reference toportable or outboard motors of the general char- 5 acter disclosed in mycopending application Serial No. 83,745, led June 5, 1936.

It is one of the principal objects of this invention to provide a light,compact motor composed of a relatively few simple parts capable of lbeing inexpensively manufactured and readily assembled.

Another object of the present invention consists in the provision of amounting for the motor rendering it possible to readily swing the motor15 to a position wherein the propeller is clear of the water and havingmeans effective to rigidly hold the motor in this position while beingcranked. In accordance with this invention, the engine is started byturning the crankshaft directly and 20 the mounting not only effectivelyprevents up and down movement of the engine during the crankingoperation, but also prevents oscillation of the engine about thesteering axis.

Another advantageous feature of the present 25 invention resides in theprovision of a mounting of the character set forth equipped with meansfor insulating the engine from the boat and for effectively absorbingvibrations instituted in the l engine so that transfer of thesevibrations to the 3 boat is reduced to the minimum.

A further object of this invention resides in the means provided hereinfor conducting fuel mixture to the combustion chamber of the engineandfor regulating the flow of fuel mixture admitted to said chamber.

Still another object of the invention consists in the simple andeffective ignition means provided for igniting the fuel mixture in thecombustion chamber.

In addition to the foregoing, the present invention contemplates aportable engine of the type specified having provision rendering itpossible to transport the motor without draining the fuel 45 from thefuel supply tank.

The foregoing, as well as other objects will be made more apparent,especially when considered in connection with the accompanying drawings,wherein:

50 Figure 1 is a sectional view through an engine constructed inaccordance with this invention;

Figure 2 is a side elevational view illustrating in full lines theposition of the engine during the cranking operation and showing' inbroken lines 55 the normal location of the engine;

Figure 3 is a rear elevation of the engine shown in Figure 1;

Figure 4 is a front elevation of the engine;

Figure 5 is a top plan view of the engine;

Figure 6 is a sectional view taken substantially 5 on the planeindicated by the line 6 6 of Figure 1;

Figure 7 is a sectional view taken substantially on the plane indicatedby the line 1-1 of Figure 1; 10

Figure 8 is a sectional View taken substantially on the plane indicatedby the line 8-8 of Figure 1;

Figure 9 is a group perspective View of the several parts of themounting; 16

Figure 10 is a cross sectional view taken substantially on the planeindicated by the line ill-I0 of Figure 1;

Figure 11 is a sectional view taken substantially on the plane indicatedby the line Il-II of Figure 3; and

Figure 12 is a cross sectional view taken substantially on the planeindicated by the line |2-i2 of Figure 1.

For the purpose of illustrating the present invention, I have selected aportable marine engine of the single cylinder type operating on the twocycle principle and having provision for removably clamping the same toa suitable boat. It will be observed that the engine is similar inprinciple to the one set forth in my above identified copendingapplication in that the cylinder of the engine is supported below thewater level during operation in order that the same will be effectivelycooled without the necessity of employing a circulating system includingwater jackets and in that the propeller, which is mounted directly onthe crankshaft, is turned directly to crank the engine when the latteris supported in its tilted position shown by the full lines in Figure 2.It will, of course, be understood that the elimination of the Waterjackets appreciably decreases the Weight of the engine and,consequently, the cost of manufacture thereof. It will also be observedthat by cranking the engine in the tilted position thereof shown inFigure 2, it is not necessary to overcome the resistance offered by theWater to rotation of the propeller and, as a result, starting of theengine is effected with less effort.

In detail, the engine proper comprises three castings, designated inFigures 1, 3, and 4 by the reference characters I5, i6, and Il. Theintermediate casting I6 is detachably secured to the top section i5 bymeans of the studs I8 and is 55 similarly secured to the bottom sectionI1 by means of the studs I8. As a result, a unitary construction isprovided capable of being readily as,

sembled and disassembled.

Upon reference to Figure 1, it will be noted that the casting I5 lsfashioned to form a fuel supply tank 28 having a top wall 2I forming asupport for the ignition coil 22 and carburetor 23. 'I'he intermediatecasting I6 1s fashioned to provide a cylinder 24 at the lower endthereof and the bottom casting I1 is fashioned to support a crankshaft25.

Referring again to Figure 1, it will be noted that fuel conduits 28 and21 are respectively cast integral with the top and intermediate castingsI5 and I6. These conduits assume a position in alignment with each otherwhen the two castings are secured together by means of the studs I8 anda liner 28 is installed in the conduits to provide a continuous passagefor the fuel mixture through the two castings. In Figure 1 of thedrawings. the location of the conduits are predetermined so that thepassage 29 extends from the carburetor 23 to the intake openings 38located in the sides of the cylinder 24. In actual practice, the conduit26 extends through the fuel tank in heat conducting relation to the fuelin the tank, and this is important in that it tends to maintain the fuelmixture flowing through the passage 29 at a more uniform temperature.

The cylinder isalso provided with an exhaust opening 3I and inaccordance with the principle of two cycle operation, both the intakeand exhaust openings are controlled by a piston 32 reciprocably mountedin the cylinder 24. In accordance with conventional practice, the topwall of the piston cooperates with the adjacent walls of the cylinder toform a combustion chamber 33 and the compressed fuel mixture in thischamber is ignited by a spark plug 34 housed in the intermediate sectionI6 of the motor. The spark plug 34 is electrically connected to the coil221 and the latter in turn is connected to the distributor 35 by meansof electrical conductors 36 extending through a conduit 31 which is castintegral with the upper section I5 of the mold. It will be observed thatthe conduit 31 also extends through the fuel tank and in this mannerexterior plumbing or accessories is reduced to the minimum.

The piston 32 is operatively connected to the eccentric crank pin 38 onthe shaft 35 by means of a connecting rod 39 in such a manner thatreciprocation of the piston effects a rotation of the crankshaft 25.This crankshaft is supported at points spaced axially thereof inanti-friction bearings 40 and the rear end of the shaft extends axiallythrough the packing gland 4I for attachment to the propeller 42. Thepropeller is protected by means of a guard 43 cast integral with thebottom section I1 in advance of the propeller and is preferably formedhollow toreduce the weight to the minimum. It may be pointed out at thistime that the propeller is prevented from sucking air by means of thecavitation fitting 44 secured to the intermediate casting I6 directlyabove the propeller blades. The cavitation fitting 44 is arcuate, asshown in Figure 3, so as to assist in turning the motor about thesteering axis 45. This plate also operates to reduce the splash when themotor is lowered in water, subsequent to the cranking operation.

As stated above, provision is made herein for turning the engine aboutthe up and down axis V45 in order to control the path of movement of theboat upon which the engine is mounted. In detail, a pair of verticallyspaced lugs 41 and 48 are cast integral with the rear wall of thesection I5 of the engine. with aligned openings therethrough forreceiving the vertical spindle 49 which is secured to the bottom lug 48by means of the set screw 5I]l and forms a bearing for the sleeve 5I.The sleeve 5I extends between the two lugs and is secured to themounting bracket assembly 52 in a manner to be more fully hereinafterdescribed. The motor is actually turned about the axis of the sleeve 5Iby means of a handle 53 having a grip 54 conveniently located formanipulation by the operator a'nd having a laterally projecting portion55 extending through a bore 56 formed in a boss cast integral with thesection I5 of the engine. The axis of the bore 56 is located in a planeperpendicular to the plane of the turning axis 45 and is offset asufficient distance in rear of the latter axis to provide for readilyturning the engine about the axis 45. Although, sufficient frictioninherently exists in the pivotal mounting for the handle to normallymaintain the latter in its operative position, nevertheless, the handlemay be readily swung downwardly when the motor is being transported, orpacked for shipping.

Referring now to the assembly 52 for mounting the engine upon a boat, itwill be noted that this assembly comprises a bracket 60 pivotallyconnected to the sleeve 5I by means of a pin 6I secured to a boss 62formed on the rear side of the sleeve 5I. The axis of the boss 62 islocated in a plane perpendicular to the steering axis 45 in order topermit the engine to be swung to either of the two positions shown inFigure 2. Upon reference to Figure 5, it will be noted that the oppositeends of the pin 6I project beyond the corresponding ends of the boss 62and extend through bosses 64 formed in the rear end of the bracketSIl. Arubber bushing 65 insulates the pin 6I from metallic contact with thebracket so that vibrations set up in the engine are absorbed prior tobeing telegraphed to the bracket 60.

The bracket 60 is provided with a downwardly` opening clamp 66 adaptedto fit over the sup-y Both of the lugs Iare provided tively insulatingthe engine from the boat. If f desired, the wall 61 may be ribbed, as at10, to increase the strength thereof while maintaining the weight -ofthe bracket to the minimum. A suitable clamping screw 1I is threaded inthe front wall of the portion 66 and this screw is provided with anenlarged head 12 which cooperates with the rear wall 61 in effectivelyclamping the motor to the boat.

With the above construction, it will be noted that the engine may beswung fromthe dotted line position thereof shown in Figure Tfbout theaxis of the pin 6I to the full line position illustrated'in the samefigure wherein the propeller 42 is located above the water level. Theengine is held in its raised position by means of a latch member 15slidably mounted in the bracket 60' swinging the motor to the abovenamed position, the operator merely pushes the latch member 15rearwardly to engage the end 16 in the opening 11. Movement of the latchmember into locking engagement with the lug 41 of the motor is cilectedagainst the action of the spring 18 which is located in a bore formed inthe bracket 60 and irictionally engages the latch member.

When the latch member is in locking engagement with the lug 41, theengine is rigidly held from swinging movement about the axis of the pin6I and, in view of the fact that the opening 11 through the lug 41 isoffset with respect to the axis of swivel movement of the engine, itfollows that the latch also-prevents oscillaltion of the engine aboutthe swivel axis 45. In other words, the engine is rigidly held againstmovement when in its tilted position shown by the full lines in Figure 2and the engine may be readily started by merely cranking the propeller42. Rotation of the propeller to effect the cranking operation isaccomplished by reeving a flexiblc member around a pulley 18 secured tothe rear face of the propeller 42 in concentric relation with thecrankshaft 25, with the result that when the exible member is unwound,the shaft is rotated sufficiently to accomplish the cranking operation.As'stated above, the propeller 42 is spaced above the water level duringthe cranking operation so that it is not necessary to overcome theresistance offered to rotation of the propeller by the water and, as aresult, starting of the engine is appreciably facilitated.

The carburetor 23 supplies fuel mixture to the combustion chamber 33through the passage 29 and this carburetor is shown in Figure 8 as beingsecured to the top wall 2| of the fuel tank or section I5 of the engine.Upon reference to Figure 1, it will be noted that both the carburetorand ignition coil 23 are enclosed by means of a cover secured to thesection I5 by the screws 8|. The side Walls of the cover 80 are slottedadjacent the carburetor to provide ports 83 through which air flows intothe Venturi .passage 84 of the carburetor. As shown in Figure 8, fuel issupplied to the Venturi passage for mixture with the air through a. jet85 controlled by a needle valve 86 threadedly mounted to vary the areaof the jet from zero to a predetermined maximum. The fuel is supplied tothe jet through the medium of a conduit 81 having one end extending intothe fuel tank 20 to a point adjacent the bottom of the latter and havingthe opposite end communicating with the valve controlled jet.

With the above construction, it will be noted that when the piston ofthe engine is on its suction stroke, fuel is drawn upwardly through theconduit 81 and is injected into the air stream passing through theventuri 84 so as to cornmingle with the air prior to being admittedthrough the intake ports 30 in the cylinder wall 2l of the engine. Thespeed of the engine or the volume of fuel mixture supplied is controlledby 'a throttle Valve 88 mounted for sliding movement transversely of theventuri opposite the fuel jet 85. It will be observed from Figure 8 thatthe inner end o-f the throttle valve extends into the venturi to varythe effective cross sec tional area thereof and that the valve is heldin any one of its several adjusted positions by means of a springpressed detent 89. This particular type of throttle valve is preferredsince it maintains the proper air and fuel ratio, irrespective of thespeed of the engine or the volume of fuel mixture supplied to thecombustion chamber.

It will. also be observed from Figure 8 that' provision is made hereinfor choking the engine by dimensioning or closing entirely the airpassage through the venturi 84. This is accomplished, in the presentinstance, by providing a vertically reciprocable valve disc 90 on thecover 80 directly above the end oi the venturi 84 and normallymaintained in its inoperative position with respect to the venturi bymeans of a spring 'I'he spring 9| surrounds a plunger 92 recip-i rocablymounted in the cover 80 and having the valve dise 90 secured to thelower end thereof. A suitable abutment 93 is secured to the upper end ofthe plunger for engagement with the corresponding end of the spring andthe opposite end oi the spring seats upon the cover. When it 1s desiredto choke the engine, the valve plunger 92 is merely depressed to seatthe disc 90 over the air intake opening of the Venturi passage 84.

In order that fuel may be drawn upwardly through the passage 81 to thecarburetor jet, provision is made herein for venting the interior of thefuel tank to the atmosphere. In Figure 11, I have shown a filler opening95 for the fuel tank adapted to be closed by means of a cap 96 having avent 91 therethrough. In the present instance, the vent is adapted to beclosed by means of a valve member 98 threaded in the cap and having anenlarged head 99 positioned for convenient manipulation by the operator.With this construction, it will be noted that by closing the vent 91with the valve 98 and by closing the jet 85 with the needle valve 86,the motor may be transported without draining the fuel tank.

Referring now more in detail to the construction of the distributor 35for controlling the ignition of the fuel mixture in the combustionchamber 33, it will be noted that this distributor comprises relativelymovable contacts |00 and |0I. fIhe contact |00 is electrically connectedto the ignition coil 22 and is supported in the intermediate casting I6of the engine by means of the flexible member or spring |02. Thecooperating contact I 0I is fixed to the intermediate casting I8 in aposition to be engaged by the contact |00 under the inuence of thespring I 02. 'Ihe contact |00 is positively moved away from the contact|0| in timed relation to the crank travel to effect ignition of the fuelmixture in the chamber 33 by means of a cam |03 secured to thecrankshaft and engaged by the lower end of a vertically movable plunger|04 having the upper end abutting the spring |02. The plunger isnormally urged into frictional engagement with the cam by means of thespring I 05 surrounding the plunger and located in aligned bores formedin the two castings I5 and |1. 'I'he arrangement is such that when thehigh point of the cam cornes in contact with the lower end of theplunger |04, the latter is raised against the action of the spring |05to move the contact |00 in a direction away from the contact IOI. On theother hand, when the lower end of the plunger passes over the high pointof the cam, the spring |02 returns the contact |00 into engagement withthe cooperating contact |0|. This relatively simple mechanism controlsthe ignition of the fuel mixture in the combustion chamber 33 andoperates efficiently without attention over a long period of time.

Upon completion of the power stroke of the engine, the burned gases areexhausted through quiet operation.

' ly noiseless.

the opening leased below the 3| in the cylinder wall and are rewaterlevel in order to provide As shown in Figure l, the exhaust opening 3lcommunicates with a vertically upwardly extending pipe H0 having theupper end communicating with a muiiler lill secured to the casting I5 bymeans of the set screw 50. The muffler, in turn, communicates with adownwardly extending pipe H2 having the lower end extending below thewater level. With this construction, extremely quiet exhaust is providedand operation of the motor is rendered practical- To avoid anypossibility of water being drawn upwardly through the muffler in theevent that the engine stalls, a small vent Ill is formed in the exhaustpassage in a position to establish communication with the atmosphere.This vent is of sumcient size to destroy any partial vacuum or suctionthat may be set up in the exhaust passage in the event the enginestalls.

Thus, from the foregoing, it will be observed that I have provided arelatively simple portable marine engine capable of being inexpensivelymanufactured and assembled. It will also be noted that the engineincorporates numerous features which not only contribute to thesimplicity of design, but also appreciably enhance the performance ofthe same.

What I claim as my invention is:

1. In a portable marine engine, the combination with an engine unitincluding a submersible propeller and means for turning the engine aboutan up and down axis for steering purposes, of means for attaching theengine unit to a support including a bracket hingedly connected to theengine unit to permit swinging the unit from a position wherein thepropeller is submerged to a position wherein the propeller is locatedabove the water level, means accessible in the last named position ofthe engine unit for cranking said engine and unitary latch means;mounted on the bracket and engageable with the engine unit in the tiltedposition to rigidly hold the engine unit against both turning andswinging movement during cranking of said engine.

2. In a portable marine engine, the combination with an engine unitincluding a submersible propeller and means for turning the engine aboutan up and down axis for steering purposes, of means for attaching theengine unit to a support including a bracket, a hinge pin extendingtransversely of the axis of turning movement of the engine unit andpivotally connecting the bracket to said engine unit permitting thelatter to be tilted from a position wherein the propeller is submergedto a position wherein the propeller is spaced above the water level,means accessible in the last named position of the engine to crank thelatter and a latch carried by the bracket and engageable in an openingin the engine unit predeterminedly located with respect to the axesaforesaid to rigidly hold the engine unit in its tilted position againstturning movement about the up and down axis aforesaid during cranking ofthe engine.

3. In a portable marine engine, the combination with an engine unitincluding a submersible propeller and means for turning the engine aboutanup and down axis for steering purposes, of means for attaching theengine unit to a support including a bracket, a hinge pin extendingtransversely of the axis of turning movement of the engine unit andpivotally connecting the bracket to said engine unit permitting thelatter to be tilted from a position wherein the propeller is submergedto a position wherein the propeller is spaced above the water level,means accessible 4 in the last named position of the engine lunit tocrank the latter, a latch carried by the bracket and engageable in anopening in the engine unit predeterminedly located with respect to theaxes aforesaid to lrigidly hold the engine unit in its tilted positionagainst movement about either the tilting or turning axis of the engineunit during the cranking operation, and resilient means insulating theengine unit from metallic contact with the bracket.

4. In a portable marine engine, the combination with an engine unithaving a fuel tank and a submersible propeller positioned below the fueltank, of a bracket for removably attaching the engine unit to a support,means supported by the fuel tank of the engine unit and connected to thebracket permitting turning movement of the engine unit about an up anddown axis relative to the bracket,'a hinge pin also carried by the fueltank and extending transversely of the turning axis to permit tilting ofthe engine from a position wherein the propeller is submerged to aposition wherein the propeller is located above the water level, andmeans carried by the bracket and engageable with the fuel tank forrigidly holding the engine unit in its tilted position against movementabout either the tilting or turning axes of the engine unit.

5. In a portable marine engine, the combination with an engine unithaving a fuel tank and having a submersible propeller, of a bracket forremovably clamping the engine unit to a support, a pin supported by thefuel tank with its axis extending substantially vertical, a sleeverotatably mounted on the pin to provide for turning movement of theengine unit about the axis of the pin, a hinge pin extendingtransversely of the axis of the turning pin and pivotally connecting thesleeve to the bracket to permit tilting of the engine from a positionwherein the propeller is submerged to a position wherein the propelleris located above the Water level, and a latch member carried by thebracket and movable into engagement with the engine unit when the latteris in its tilted position to rigidly hold the engine unit in saidposition against movement about the axes of said pins.

6. In a portable marine engine, the combination with an engine unithaving a submersible propeller and having an exhaust conduit with theoutlet end adapted to extend below the water level, of means for turningthe' engine about an up and down axis for steering purposes, means forattaching the engine unit to a support including a bracket hingedlyconnected to the engine unit in a manner to permit swinging of theengine unit to a position wherein the propeller and outlet end of theexhaust are submerged to a position wherein the propeller and outlet endof the exhaust are located above the water level, means accessible inthe last named position of the engine unit for cranking said engine, andunitary latch means mounted on the bracket and engageable with a part ofthe engine unit in the tilted position thereof to hold the engine unitagainst turning and swinging movement during cranking of the engine.

7. In a portable marine engine, the combination with an engine unitincluding a submersible propeller and means for turning the engine aboutan up and down axis for steering purposes, of means for attaching theengine unit to a supi. pore windings hinge pin extending ineens forattaching the engine unit to a sup- 'j tran'gYE'selyJJotftheixis 'ofturning movement ot port lincluding a bracket unit hingedly connected ,i.jthc engine pivotally connecting the latter tothe engine to permitswinging the latter from a ,to the 'bracket to permit the engine unit tobe position wherein the propeller is submerged to y V`f 'ly1hold theengine unit in a tilted position against the Water level, and a singlelatch element vboth turning and swinging movement relative to mounted onone of the units and engageable with the bracket. the other unit in thetilted position of the engine 8. In a portable marine engine, thecomhinnto rigidly hold the latter against both turning 10 tion with anengine unit including a aubmersible and swinging movement.

propeller and means for turning the engine aboutanupanddownaxisforxteerlngpurpocesmt DOUGLABRCLARKE.

I; 15 tilted. 'and unitary latch means eii'ective to rigida positionwherein the propeller is located above

